The present invention relates to an artificial marble, which is prepared by use of chips containing a low specific gravity material (having a specific gravity of 0.2˜2.0) to realize a natural stone-like texture, and a process for preparing the artificial marble. More particularly, the present invention relates to an artificial marble wherein a low specific gravity material, which could not be used in conventional artificial marbles, is used to constitute artificial marble chips having a relatively high specific gravity via a lamination or crunch technique, so as to achieve a texture remarkably similar to that of natural stone, and a process for preparing the artificial marble.
Artificial marbles refer collectively to artificial synthetic products prepared by blending natural stone powder and minerals with a resin component (acrylic, unsaturated polyester, epoxy, etc.) or cement and adding various kinds of pigments and additives to the blend so as to realize a natural stone-like texture. Representative artificial marbles include acrylic artificial marbles, unsaturated polyester artificial marbles, engineered stone artificial marbles, and the like.
Here, engineered stone artificial marbles are prepared by blending natural stone powder, quartz, glass, mirror, aluminum hydroxide, etc. as main materials with 15 wt % or less of resin, and hereinafter, referred to as “E-stone”.
Most conventional artificial marble products generally have a single color, or a simple outer appearance using only few colors of chips. Much research for developing artificial marbles imitating the outer appearance of natural marbles has been carried out.
As known, low specific gravity materials, such as acrylic materials, etc., rise up above slurry due to a specific gravity difference when being used alone. Therefore, in the case of chips made of the low specific gravity materials, they may exhibit a separation from other chips having a relatively high specific gravity, thus making it impossible for artificial marble products to achieve a desired surface texture. For this reason, conventionally, low specific gravity materials could not be used in the preparation of artificial marbles.
Korean Patent Laid-open No. 2004-59913 discloses an acrylic artificial marble featuring the use of special chips each containing various colors of chips therein (referred to as “chip-in-chip”). However, the disclosed acrylic artificial marble is a mere combination of materials having specific gravities similar to one another for the sake of color effect, and has a problem of low transparency because of an inorganic filler contained in a composite thereof.
Korean Patent Registration No. 376605 discloses an artificial marble panel containing chips. In the disclosed artificial marble panel, a variety of chips having different specific gravities and colors from one another are dispersed in such a manner that low, medium, and high specific gravity chips are dispersed to a front surface, mid-portion, and backside of the panel, to diversify the pattern and color of the resulting panel. The above Patent, however, proposes to separate layers by differentiating the specific gravity of chips, unlike the present invention.
Korean Patent Registration No. 491874 discloses an artificial marble comprising: (A) 100 parts by weight of an artificial marble slurry containing 100 parts by weight of an acrylic resin syrup, 120˜200 parts by weight of an inorganic filler, 2˜10 parts by weight of a cross-linking agent, and 0.1˜10 parts by weight of a polymerization initiator, and (B) 5˜70 parts by weight of marble chips containing 100 parts by weight of an acrylic resin syrup, 100˜150 parts by weight of an inorganic filler, 2˜10 parts by weight of a cross-linking agent, and 0.1˜10 parts by weight of a polymerization initiator, wherein the mixing rate of the inorganic filler in the artificial marble slurry is greater than that in the marble chips by 20˜50 parts by weight. The artificial marble, disclosed in the above Patent, however, has deterioration in transparency because of the inorganic filler added in the marble chips.
Japanese Patent Registration No. 3648592 discloses an artificial marble using a variety of chips having different shapes and specific gravities from one another. The above Patent has no relation with utilization of low specific gravity materials for increasing the specific gravity of the materials as proposed by the present invention.
Japanese Patent Registration No. 3685116 discloses an artificial marble prepared by heating and curing a resin compound containing a heat-curable resin as a main component. The disclosed artificial marble has a feature in that a front surface thereof is formed of a non-foamed artificial marble layer and a backside thereof is formed of a foamed artificial marble layer having a lower density than that of the non-foamed artificial marble layer. In the case of the invention disclosed in the above Patent, although it shows an improvement in the installation of fasteners as well as the recycling, cutting, and other processes of the artificial marble by virtue of the foamed layer at the backside of the artificial marble, it has no relation with utilization of low specific gravity materials for increasing the specific gravity of the materials as proposed by the present invention.
Japanese Patent Laid-open No. 1999-343156 discloses a lightweight artificial marble prepared by blending 100 parts by weight of an artificial marble syrup with 20˜180 parts by weight of a foamed inorganic particle-shaped material, which has a specific gravity of 0.5˜1.5 and an average particle diameter of 3 mm or less, and heating and polymerizing the blend. Japanese Patent Laid-open No. 2001-335382 discloses a lightweight artificial marble composite comprising: 10˜65 wt % of a polymerizable component containing methyl methacrylate as a main component, 30˜85 wt % of an inorganic filler, and 0.1˜10 wt % of an organic hollow filler having a specific gravity of 0.05˜0.7 and an average particle diameter of 10˜300 μm. The above-described patents deal with only a reduction in the weight of artificial marbles, and have no relation with utilization of low specific gravity materials for increasing the specific gravity of the materials as proposed by the present invention.